Further adding to market fear, a van crashed into dozens of people in the center of Barcelona on Thursday, with the Spanish media, citing police sources, said at least 13 were killed, Reuters reports. Catalan police were treating the crash as a terror attack.

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Investors were also wary of the economic outlook, following Trump’s disbanding of two business councils Wednesday after several chief executives quit over remarks on white nationalists. Traders were concerned that the action would further distract the administration from its pro-growth agenda of tax cuts, deregulation and increased fiscal spending.

“There’s a lot of little things weighing on people’s minds and it makes for a quicker decision to get out,” Peter Costa, president of Empire Executions Inc, told Reuters. “People are becoming a little more skeptical about market valuations. Even though the economy is doing fairly well and you’ve a host of positives, people get a little nervous when you get close to long-term highs.”

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